No power problems

[mr.travo]

Have everything hooked up and jump box on the truck. We are getting zero power to anything inside. Getting 24 and 12 under the hood. Any ideas? We're stumped.

 

[Mainsail]

There is a fusible link that runs to the little 12v bus on the firewall behind the glow plug relay. Do you have voltage at that bus bar?

 

[Ferroequinologist]

Yes, power all the way to the 12v bus above the glow plug solenoid. Fusible links are all good past that as well. If we jump 12v to the output on the driver side alternator everything powers up and it will start and run. Take the wire off she dies.

 

[mr.travo]

We got it fixed thanks to Ferroequinologist! It was a fusible link that ran on the firewall from the buss bar.

Thanks Adam!

 

[mr.travo]

Well replaced the fuseable link on the firewall with one that was good. Still no joy. I am opened to ideas. This one has me scratching my head.

 

[Mainsail]

The fuse box on the firewall is a choke point. Do you have power inside the truck anywhere on the panel? If not can the panel be bad? I've never dived that deep, but it sounds like a choke-point problem.

 

[mr.travo]

The fuse box on the firewall is a choke point. Do you have power inside the truck anywhere on the panel? If not can the panel be bad? I've never dived that deep, but it sounds like a choke-point problem.

That's what I was thinking but have power to some of the fuses. Once you jump the positive on the back of the drivers side gen to the GP relay, everything in the truck works and it fires up. I haven't seen this before.


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[richingalveston]

The first simple thing to check is your case ground on alt 1, if it is missing funny things can happen but this does not sound like your problem.

check the plug on the back of gen 1. it sounds like you may have a bad exciter wire to alt1. and possibly a bad diode trio in alt 1. The power to the exciter wire should come from the fuse box. The power from the fuse box comes from the 12v terminal block. There is a fuse for this check that.

If you have power from the battery to the 12 volt terminal block then with the ignition on, all fuses in the fuse box should be hot with or without the engine running. With only some fuses working, it sounds like you have a bad fuse box. Which could have led to a bad diode trio and alt.

It seams you have a break in the fuse box and when you connect power to output of gen 1 it back feeds to the fuse box lighting up the fuses that are on the other side of the break. IF power is back feeding through your alt, the diode trio is bad.

Your first post states you got it all hooked up. was there a previous problem you fixed.

just trying to help with your gremlin.
Rich

 

[mr.travo]

The first simple thing to check is your case ground on alt 1, if it is missing funny things can happen but this does not sound like your problem.

check the plug on the back of gen 1. it sounds like you may have a bad exciter wire to alt1. and possibly a bad diode trio in alt 1. The power to the exciter wire should come from the fuse box. The power from the fuse box comes from the 12v terminal block. There is a fuse for this check that.

If you have power from the battery to the 12 volt terminal block then with the ignition on, all fuses in the fuse box should be hot with or without the engine running. With only some fuses working, it sounds like you have a bad fuse box. Which could have led to a bad diode trio and alt.

It seams you have a break in the fuse box and when you connect power to output of gen 1 it back feeds to the fuse box lighting up the fuses that are on the other side of the break. IF power is back feeding through your alt, the diode trio is bad.

Your first post states you got it all hooked up. was there a previous problem you fixed.

just trying to help with your gremlin.
Rich

Thanks Rich! Truck sat for a couple of years. Everything seemed good and installed new bus bar on it that was borrowed for another CUCV. The batteries are shot but had it powered off a 24v jump box (yes I was getting proper voltage). Today I ran if off of the slave cables off my 1009. I have never seen dead batteries be any issue when hooked up to slave cables. I cleaned the ground off Gen 1 today and still nothing. We also think that when we run the jumper it's back feeding the system as well.

We replaced Gen 1 last night because the positive stud was spinning when we tried to unbolt it.

The 20 and 30 level books are no help on this issue.


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[mr.travo]

The first simple thing to check is your case ground on alt 1, if it is missing funny things can happen but this does not sound like your problem.

check the plug on the back of gen 1. it sounds like you may have a bad exciter wire to alt1. and possibly a bad diode trio in alt 1. The power to the exciter wire should come from the fuse box. The power from the fuse box comes from the 12v terminal block. There is a fuse for this check that.

If you have power from the battery to the 12 volt terminal block then with the ignition on, all fuses in the fuse box should be hot with or without the engine running. With only some fuses working, it sounds like you have a bad fuse box. Which could have led to a bad diode trio and alt.

It seams you have a break in the fuse box and when you connect power to output of gen 1 it back feeds to the fuse box lighting up the fuses that are on the other side of the break. IF power is back feeding through your alt, the diode trio is bad.

Your first post states you got it all hooked up. was there a previous problem you fixed.

just trying to help with your gremlin.
Rich

Rich-

Forgot to tell you that I did notice a large voltage drove on the 12v bus with the key on. It would drop to ~4v and the GP relay wasn't engaged or anything. What do you think that points to?

Thanks!


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[richingalveston]

I would pull the batts out of the 1009 and put them in and try it. if the old batts are dead, they can create a dead short and drain themselves. Also. the power system is a linear circuit pos. and negative are actually supply and return thus bad batteries can break the path and cause it to have to travel two different directions. before wasting more time I would do this first.

 

[mr.travo]

I would pull the batts out of the 1009 and put them in and try it. if the old batts are dead, they can create a dead short and drain themselves. Also. the power system is a linear circuit pos. and negative are actually supply and return thus bad batteries can break the path and cause it to have to travel two different directions. before wasting more time I would do this first.

Awesome. Ok we have two new batteries for it. I'll get them dropped in tomorrow and report back what happens.

I appreciate the help!

Travo


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[richingalveston]

just as an fyi, your slave plug hooks into the electrical system on the 24volt side. Thus if there is a dead short in the front battery, your 12 volt system becomes divided.
Running the system with a bad front battery breaking the system can cause the alternator to fail.

 

[mr.travo]

just as an fyi, your slave plug hooks into the electrical system on the 24volt side. Thus if there is a dead short in the front battery, your 12 volt system becomes divided.
Running the system with a bad front battery breaking the system can cause the alternator to fail.

With key off engine off I was getting 12-14v at the 12v buss. Once I turned the key on I was getting around 4v. I didn't think about having a dead short in the battery. I think you are on to something. I will pop in those new batteries and see what happens tomorrow.




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[llong66]

If that does not fix your problem, have you pulled the fuse block apart? You said the truck sat for a cpl years, there is one bolt on the dog house side that lets you pull the entire plug, after a cpl of years, who knows what could be in there. If that looks ok after a good cleaning, the fuse box on the inside comes off the fire wall with I believe two bolts and you can pull it apart and have a look at the back of the inside part.

 

[mr.travo]

If that does not fix your problem, have you pulled the fuse block apart? You said the truck sat for a cpl years, there is one bolt on the dog house side that lets you pull the entire plug, after a cpl of years, who knows what could be in there. If that looks ok after a good cleaning, the fuse box on the inside comes off the fire wall with I believe two bolts and you can pull it apart and have a look at the back of the inside part.

Right on. If this doesn't do the trick I'll continue on to that. LOL! This issue is really strange. I'll be happy to chalk it up to knowledge once we getting it firing off.

 

[mr.travo]

Thank you for the help guys! Ended up being a shorted out battery. We put the new ones in and it busted right off. It still purrs like a kitten. Problem solved and knowledge gained!

 

[richingalveston]

make sure you have done the doghead mod if it has not been done. go through the stickies in the cucv section and it will help you to make your truck dependable.

glad it worked out.

Rich

 

[mr.travo]

make sure you have done the doghead mod if it has not been done. go through the stickies in the cucv section and it will help you to make your truck dependable.

glad it worked out.

Rich

Oh absolutely! All of mine get the Doghead Mod! This one is for a friend but it's also on the list. Spent the afternoon chasing down other electrical faults (Gen 2 light) and getting the next in line smaller stuff taken care of. After electrical, it's mechanical, then body and paint. Really excited to see this one done right. It was my old work truck back before I retired. Kind of a funny situation but glad to know who it's going to.